This invention relates to a lifting mechanism for removing and replacing the cover of a spa.
The use of outdoor spas has become widespread, particularly in the regions of the country that enjoy generally warm weather. Most outdoor spas are equipped with covers which when closed, prevents debris, rain and the like from contaminating the tub water when the spa is not being utilized. The cover further serves to retain heat within the tub to help maintain the water at a desired temperature level. As a consequence, spa covers tend to be relatively heavy and thus difficult to remove and replace.
Lifting devices have been developed to aid in the removal and replacement of these relatively heavy spa covers which can be operated with varying amounts of difficulty by one person. One such lifting device is disclosed in U.S. Pat. No. 5,131,102 to Salley et al. A pair of lifting arms is pivotally mounted along the back wall of a spa and the extended ends of the arms are, in turn, conjoined by a bridge arm that passes over the cover along the center hinge of the cover. To remove the cover, the two half sections of the cover are folded over the bridge arm and the lifting arm is then rotated upwardly and rearwardly to bring the cover to a raised position adjacent to the rear wall of the spa. Although this lifting mechanism works well in practice, the bridge arm tends to become angularly offset when the operator pulls on one or the other of the lifting arms. This in turn can produce excessive wear on the cover and misalignment of the cover. In addition, this lifting arm arrangement provides only a limited amount of mechanical advantage to the operator.
Walls et al., U.S. Pat. No. 5,048,153, describes a similar lifting mechanism for a spa cover in which the extended ends of the lifting arms are securely attached to the opposed side walls of the spa cover using a hinge plate and pivot mechanism. The lifting arms are equipped with spring loaded struts which absorb the weight of the cover as it is rotated into an open position. Again, this type of lifting mechanism has a limited mechanical advantage and the hinge plate connections produce excessive wear on the cover. Lastly, this type of lifting mechanism does not have the adjustability such that it can be adapted for use in association with various sized spas.